Diaminopyrazoles

ABSTRACT

This invention concerns the treatment of smooth muscle spasticity or excess muscle contraction such as urge urinary incontinence with a compound of the formula                    
     wherein: 
     R 1  and R 2  are independently straight chain alkyl of 1 to 6 carbon atoms, branched alkyl of 3 to 6 carbons atoms, or cycloalkyl of 3 to 6 carbons atoms where R 1  R 2  may be substituted by F, Cl, Br, I, OH, NH 2 , cyano, C 1 -C 6  alkoxy, C 1 -C 6 alkylthio, COOH or COOC 1 -C 6  alkyl; 
     R 3  is an aryl or heteroaryl as defined herein, optionally substituted with 0 to 4 groups selected independently from C 1 -C 6  alkyl, C 1 -C 6  alkoxy, cyano, F, Cl, Br, C 1 -C 6  alkylthio, CO 2 R 1 , CONH 2 , OH, NH 2 , and NO 2 ; 
     n is 0 or 1; 
     R 4  is a straight chain alkyl group of 1 to 10 carbons atoms, a branched alkyl of 3 to 10 carbons, or a cycloalkyl of 3 to 10 carbons; 
     and all crystalline forms and the pharmaceutically acceptable salts thereof

This application is a divisional application of U.S. Ser. No.09/327,065, filed Jun. 7, 1999 now, 6,172,222 which claims benefit ofprior U.S. Provisional application No. 60/099,348, filed Jun. 8, 1998.

FIELD OF INVENTION

This invention concerns 4,5-diamino derivatives of (1H)-pyrazoles andtheir use in the treatment of disorders associated with smooth musclecontraction. Such disorders include, but are not limited to, urinaryincontinence, hypertension, asthma, premature labor, irritable bowelsyndrome, congestive heart failure, angina, and cerebral vasculardisease.

BACKGROUND OF THE INVENTION

Urge urinary incontinence, the abnormal spontaneous contraction of thebladder detrusor muscle leading to a sense of urinary urgency andinvoluntary urine loss is currently a condition where there exists anunmet medical need (Primeau et al., Current Pharmaceutical Design, 1995,1, 391). The current treatments for this condition are the use ofanticholinergics and anticholinergic/antispasmodics which have thelimitations of CNS related side effects and low efficacy which leads topoor patient compliance. Hyperpolarization of bladder smooth muscleleading to the relaxation of detrusor muscle contractions may representa novel therapeutic approach to urge urinary incontinence.

Few examples of simple 4,5-diaminopyrazoles have appeared in thechemical or patent literature. Moderhack describes the synthesis ofseveral 4,5-diaminopyrazoles as intermediates towards the synthesis of1,2,4-triazoles (Liebigs Ann. 1996, 777-9). Lewis et al. describe thesynthesis of various 4,5-diaminopyrazoles (J. Heterocyclic Chem. 1983,20, 1501-3).

The synthetic procedure used to make the diamninopyrazoles reported inthis invention record is based on the procedure of Vicentini et al.(Tetrahedron 1990, 46, 5777-88 and Tetrahedron Lett. 1988, 29, 6171-2)which outlines the synthesis of 4-nitroso-5-aminopyrazoles asintermediates in the synthesis of imnidazole[4,5-c]pyrazoles.

SUMMARY OF THE INVENTION

The present invention discloses compounds represented by the formula(I):

wherein:

R¹ and R² are independently straight chain alkyl of 1 to 6 carbon atoms,branched alkyl of 3 to 6 carbons atoms, or cycloalkyl of 3 to 6 carbonsatoms where R¹ R² may be optionally substituted by F, Cl, Br, I, OH,NH₂, cyano, C₁-C₆ alkoxy, C₁-C₆ alkylthio, COOH or COOC₁-C₆ alkyl;

R³ is an aryl or heteroaryl, optionally substituted with 1 to 4 groupsselected independently from straight chain C₁-C₆ alkyl, branched alkylof 3 to 6 carbons, or a cycloalkyl of 3 to 10 carbons; C₁-C₆ alkoxy,cyano, F, Cl, Br, C₁-C₆ alkylthio, CO₂R¹, CONH₂, OH, NH₂, and NO₂;wherein aryl is phenyl, naphthalene, anthracene or phenanthrene andheteroaryl is furan, thiophene, pyrrole, irnidazole, oxazole, thiazole,isoxazole, pyrazole, isothiazole, oxadiazole, triazole, thiadiazole,quinolizine, quinoline, isoquinoline, cinnoline, phthalazine,quinazoline, quinoxaline, naphthyridine, pterine, pyridine, pyrazine,pyrimidine, pyridazine, pyran and triazine;

n is 0 or 1;

R⁴ is a straight chain alkyl group of 1 to 10 carbons atoms, a branchedalkyl of 3 to 10 carbons, a cycloalkyl of 3 to 10 carbons, all of whichmay be optionally substituted by one or more F or Cl atoms; and allcrystalline forms, enantiomers, diastereomers, and the pharmaceuticallyacceptable salts thereof.

It is understood that the definition of the compounds of formula (I),when R¹, R², R³, or R⁴, contain asymmetric carbons, encompass allpossible stereoisomers and mixtures thereof which possess the activitydiscussed below. In particular, it encompasses racemic modifications andany optical isomers which possess the indicated activity. Opticalisomers may be obtained in pure form by standard separation techniques.It is also understood that solid invention compounds or pharmaceuticallyacceptable salts thereof may exist in more than one crystalline form.The form obtained may be dependent upon the crystallization orrecyrstallization solvent or solvent mixture, the rate of heating and/orcooling, drying conditions, and other variables. The pharmaceuticallyacceptable salts are those derived from such organic and inorganic acidsas: lactic, citric, acetic, tartaric, succinic, maleic, malonic,hydrochloric, hydrobromic, phosphoric, nitric, sulfuric,methanesulfonic, and similarly known acceptable acids. Where R² or R³contains a carboxyl group, salts of the compounds of this invention maybe formed with bases such as alkali metals (Na, K, Li) or the alkalineearth metals (Ca or Mg).

The compounds of formula (I) have been found to relax smooth muscle.They are therefore useful in the treatment of disorders associated withsmooth muscle contraction, disorders involving excessive smooth musclecontraction of the urinary tract (such as incontinence), or of thegastro-intestinal tract (such as irritable bowel syndrome), asthma, andhair loss. Furthermore, the compounds of formula (I) relax bladdersmooth muscle precontracted with KCl and thus are active as potassiumchannel activators which render them useful for treatment of peripheralvascular disease, hypertension, congestive heart failure, stroke,anxiety, cerebral anoxia and other neurodegenerative disorders (J. R.Empfield and Keith Russell, “Potassium Channel Openers,” Annual Reportsin Medicinal Chemistry (1995).

DETAILED DESCRIPTION OF THE INVENTION

The present invention also provides a process for the preparation of acompound of formula (I). More particularly, the compounds of formula (I)where n is 1 may be prepared by reacting a compound of formula (II):

with a compound of formula (III):

where R³ is an aryl or a heteroaryl moiety optionally substituted with 1to 4 groups as defined previously, in a solvent such as benzene ortoluene in the presence of molecular sieves at room temperature,followed by treatment with hydrogen under a pressure of 1 atmosphere inthe presence of Pd/BaSO₄ at room temperature, in a polar solvent such asethyl acetate.

Reaction of compound of formula (II) with a compound of formula (IV):

where R³ is an aryl or heteroaryl moiety as defined previously, in asolvent such as benzene or toluene in the presence of Pd₂dba₃,P(o-tolyl)₃, and NaOt-Bu at 100° C. gives a formula (I) compound where nis 0. The compounds of formula II are prepared by procedures based onthe procedure reported by Vicentini et al., Tetrahedron 1990, 46,5777-5788 and Tetrahedron Lett. 1988, 29, 6171-6172 as given in steps1-4 in Example 1.

The following examples are included for illustrative purposes only andare not to be construed as limiting to this disclosure in any way. Thechemicals and intermediates are either commercially available or readilyprepared according to standard literature procedures. Still othermethods of preparation of invention compounds may be apparent to thoseskilled in the art of organic synthesis.

EXAMPLE 1N(3)-(2,2-Dimethyl-propyl)-2,5-dimethyl-N(4)-pyridin-4-ylmethyl-2H-pyrazole-3,4-diamineStep 1 N-(2,5-Dimethyl-2H-pyrazol-3-yl)-2,2-dimethyl-propionamide

To 15.0 g (131 mmol) N-(2,5-dimethyl-2H-pyrazol-3-yl)-amine in 150 mLpyridine at 0° C. was added 19.3 mL (18.9 g, 158 mmol) of pivaloylchloride. After stirring at 23° C. for 3.5 hours, the reaction solventwas evaporated, and the residue was evaporated with 2×200 mL toluene.The remaining solid was dissolved in 500 mL EtOAc/200 mL H₂O andextracted. The aqueous layer was extracted with 2×100 mL EtOAc, and thecombined organics were washed with 1×200 mL brine, dried over MgSO₄,filtered and evaporated to an orange solid. Recrystallization from hothexanes/EtOAc gave 24.45 g (125 mmol, a 96% yield) of the title compoundas an off-white, crystalline solid: mp: 86-88° C.; ¹H NMR (300 MHz,CDCl₃): δ1.32 (s, 9H), 2.22 (s, 3H), 3.63 (s, 3H), 5.98 (s, 1H), 7.12(brs, 1H); IR (KBr, cm⁻¹): 3316s, 3274s, 2967m, 2935m, 1673s, 1655m,1570s, 1514m, 1492m, 1457m; MS (ES) m/z (relative intensity): (196, M⁺,100).

Anal. Calcd. for C₁₀H₁₇N₃O: C, 61.51; H, 8.77; N, 21.52.

Found: C, 61.33; H, 8.80; N, 21.23.

Step 2 (2,2-Dimethyl-propyl)-(2,5-dimethyl-2H-pyrazol-3-yl)-amine

To 4.7 g (123 mmol) of LiAlH₄ in 150 mL of THF at 0° C. was added asolution of 12.0 g (61.45 mmol) ofN-(2,5-dimethyl-2H-pyrazol-3-yl)-2,2-dimethyl-propionamide and 100 mLTHF in drops over 60 min. After addition is complete, the reactionmixture was heated to 67° C. for 42 h. After cooling to 23° C., 5 mL H₂Owas carefully added, followed by 5 mL 5N NaOH and 5 mL H₂O. Theresulting mixture was filtered through Celite, evaporated to a yellowoil, dissolved in 300 mL EtOAc, washed with 1×100 mL brine, 1×100 mLH₂O, 1×100 mL brine, dried over MgSO₄, filtered and evaporated to give9.45 g (52.1 mmol, an 85% yield) of the title compound as a light yellowoil. ¹H NMR (300 MHz, CDCl₃): δ0.98 (s, 9H), 2.17 (s, 3H), 2.81 (m, 2H),3.56 (s, 3H), 5.24 (s, 1H); IR (KBr, cm−¹): 3261m, 2956m, 2866m, 1568s,1476m, 1367m, 1362m, 1267m, 1200m, 729m; MS (ES) m/z (relativeintensity): 182 (M⁺+H, 100).

Anal. Calcd. for C₁₀H₁₉N₃: C, 66.26; H, 10.56; N, 23.18.

Found: C, 64.75; H, 10.23; N, 24.67.

Step 3(2,5-Dimethyl-4-nitroso-2H-pyrazol-3-yl)-(2,2-dimethyl-propyl)-amine

To a 0° C. solution of 8.43 g (46.5 mmol) of(2,2-dimethyl-propyl)-(2,5-dimethyl-2H-pyrazol-3-yl)-amine and 150 mLEtOH was added 20 mL of 10-20% EtONO/EtOH. After stirring at 23° C. for17 h, and 21 h, 20 mL portions of 10-20% EtONO/EtOH were added. After atotal of 42 h, the reaction mixture was evaporated to a purple oil.Flash chromatography on silica gel, eluting with CH₂Cl₂/EtOAc (8/1 to4/1 to 2/1), gave a purple solid. Recrystallization from hothexanes/EtOAc gave 4.04 g (19.2 mmol, a 41% yield) of the title compoundas a violet crystalline solid. mp: 83-84° C.; ¹H NMR (300 MHz, CDCl₃):δ1.02 (s, 9H), 2.61 (s, 3H), 3.24 (d, J=6.0 Hz, 2H), 3.76 (s, 3H), 10.23(brs, 1H); IR (KBr, cm⁻¹): 3428w, 3058w, 2963m, 2872w, 1633s, 1550m,1479w, 1428w, 1222brm, 1134m, 971m; MS (ES) m/z (relative intensity):211 (M⁺+H, 100).

Anal. Calcd. for C₁₀H₁₈N₄O: C, 57.12; H, 8.63; N, 26.64.

Found: C, 57.18; H, 8.83; N, 26.69.

Step 4 N(3)-(2,2-Dimethyl-propyl)-2,5-dimethyl-2H-pyrazole-3,4-diamine

(2,5-Dimethyl-4-nitroso-2H-pyrazol-3-yl)-(2,2-dimethyl-propyl)-amine(3.44 g, 16.36 mmol), 400 mg of 10% Pd/C and 60 mL EtOAc were placedunder a balloon of H₂ and stirred at 23° C. After 4 h, the reactionmixture was filtered through Celite and evaporated to an orange oil.Flash chromatography on silica gel, eluting with CHCl₃/MeOH (20/1), gavea yellow solid. Recrystallization from hot hexanes/EtOAc gave 2.86 g(14.57 mmol, an 89% yield) of the title compound as an off-whitecrystalline solid. mp: 65-69° C.; ¹H NMR (300 MHz, CDCl₃): δ1.00 (s,9H), 1.65 (brs, 2H), 2.13 (s, 3H), 2.77 (brs, 2H), 2.89 (brs, 1H), 3.62(s, 3H); IR (KBr, cm⁻¹): 3347-3204brs, 2952s, 2903w, 1599m, 1528m,1495m, 1477m, 1378m, 1316m; MS (ES) m/z (relative intensity): 197 (M⁺+H,100).

Anal. Calcd. for C₁₀H₂₀N₄: C, 61.19; H, 10.27; N, 28.54.

Found: C, 56.19; H, 10.56; N, 26.37

Step 5N(3)-(2,2-Dimethyl-propyl)-2,5-dimethyl-N(4)-pyridin-4-ylmethyl-2H-pyrazole-3,4-diamine

To 400 mg (2.03 mmol) ofN(3)-(2,2-dimethyl-propyl)-2,5-dimethyl-2H-pyrazole-3,4-diamine and 15mL toluene was added 0.23 mL (261 mg, 2.44 mmol) of4-pyridinecarboxaldehyde, 500 mg of powdered 4Å molecular sieves and 1crystal of p-TsOH·H₂O. After stirring at room temperature for 14 h, TLCindicated that the starting amine (R_(f)=0.40 (10/1 CHCl₃/MeOH)) hadbeen converted to the imine (R_(f)=0.50 (10/1 CHCl₃/MeOH). The mixturewas filtered through Celite and evaporated to give a yellow oil.

To this oil was added 20 mL EtOAc, 300 mg 5% Pd/BaSO₄ and 1 drop ofquinoline. This mixture was placed under a balloon of H₂, and stirred atroom temperature. After 24 h, 200 mg of 5% Pd/BaSO₄ was added and thereaction mixture was again stirred under a balloon of H₂ at roomtemperature. After a total of 30 h, TLC indicated that practically allof the starting imine (R_(f)=0.50 (10/1 CHCl₃/MeOH) had been convertedto the corresponding amine (R_(f)=0.35 (10/1 CHCl₃/MeOH). The reactionmixture was filtered through Celite and evaporated to an orange oil.Flash chromatography on silica gel, eluting with CHCl₃/MeOH (40/1 to20/1 to 10/1), gave a yellow solid. Recrystallization from hothexanes/Et₂O gave 315 mg (1.10 mmol, a 54% yield) of the title compoundas a yellow crystalline solid. mp: 88-90° C., ¹H NMR (300 MHz, CDCl₃):δ0.94 (s, 9H), 1.70 (brs, 1H), 2.13 (s, 3H), 2.61 (brd, 2H), 2.81-2.90(brm, 1H), 3.59 (s, 3H), 4.00 (s, 2H), 7.26-7.33 (m, 2H), 8.53-8.60 (m,2H), IR (KBr, cm⁻¹): 3254s, 3047w, 2954m, 2865w, 1604w, 1567m, 1417m,1389w, MS (ES) m/z (relative intensity): 288 (M⁺+H, 70).

Anal. Calcd. for C₁₆H₂₅N₅: C, 66.87; H, 8.77; N, 24.37.

Found: C, 66.74; H, 8.73; N, 24.20.

EXAMPLE 2 4-{[5-(2,2-Dimethyl-propylamino)-1,3-dimethyl-1H-pyrazol-4-ylamino]-methyl}-benzonitrile

The title compound was prepared according to the procedure for Example1, Step 5 except that 4-cyanobenzaldehyde was used in place of4-pyridinecarboxaldehyde and the final product was isolated as thetosylate salt, prepared by stirring the product with 1 equiv. ofp-TsOH·H₂O in 15 mL Et₂O and removing the solvent via rotaryevaporation. Off-white solid, yield: 85%, mp: 102-104° C., ¹H NMR (300MHz, CDCl₃): δ0.78 (s, 9H), 2.00 (s, 3H), 2.20-2.40 (brm, 1H), 3.64 (s,3H), 4.20-4.50 (brm, 1H), 4.37 (s, 2H), 7.21 (d, J=8.1 Hz, 2H), 7.39 (d,J=8.1 Hz, 2H), 7.50-7.55 (m, 2H), 7.74 (d, J=8.1 Hz 2H), IR (KBr, cm⁻¹):3500-2300brm, 3333m, 2957m, 2865m, 2230m, 1606m, 1592m, 1497w, 1477m,1216s, 1158s, 1124s, 1032s, 1009s, 819s, 683s, MS (ES) m/z (relativeintensity): 312 (M⁺-p-TsOH+H, 100).

Anal. Calcd. for C₂₅H₃₃N₅O₃S: C, 62.09; H, 6.88; N, 14.48.

Found: C, 59.00; H, 6.30; N, 13.18.

EXAMPLE 3N(3)-(2,2-Dimethyl-propyl)-N(4)-(4-fluoro-benzyl)-2,5-dimethyl-2H-pyrazole-3,4-diamine

The title compound was prepared according to the procedure for Example1, Step 5 except that 4-fluorobenzaldehyde was used in place of4-pyridinecarboxaldehyde. Yellow solid, yield: 78%, mp: 32-39° C., ¹HNMR (300 MHz, CDCl₃): δ0.93 (s, 9H), 2.11 (s, 3H), 2.55 (s, 2H), 3.59(s, 3H), 3.93 (s, 2H), 7.01 (m, 2H), 7.27 (m, 2H), IR (KBr, cm⁻¹):3334m, 3272s, 2960m, 2918m, 2869m, 1891w, 1592m, 1508s, 1479s, 1462s,1364s, 1303s, 1283s, 1224m, 1140m, 993m, 819s, 725s, MS (ES) m/z(relative intensity): 305 (M+H⁺, 100).

Anal. Calcd. for C₁₇H₂₅FN₄: C, 67.08; H, 8.28; N, 18.40.

Found: C, 66.58; H, 8.54; N, 18.07.

EXAMPLE 4N(4)-(2,4-Dichloro-benzyl)-N(3)-(2,2-dimethyl-propyl)-2,5-dimethyl-2H-pyrazole-3,4-diamine

The title compound was prepared according to the procedure of Example 1,Step 5 except that 2,4-dichlorobenzaldehyde was used in place of4-pyridinecarboxaldehyde and the final product was isolated as thetosylate salt by dissolving in 20 mL Et₂O and stirring with 1 equiv. ofp-TsOH·H₂O for 1 h, and removing the solvent via rotary evaporation.Off-white solid, yield: 50%, ¹H NMR (300 MHz, CDCl₃): δ0.84 (s, 9H),1.25 (s, 1H), 2.02 (s, 3H), 2.38 (s, 3H), 2.56 (brs, 1H), 3.71 (s, 3H),4.26 (s, 2H), 4.29 (s, 2H), 7.10-7.50 (m, 5H), 7.77 (s, J=8.2 Hz, 2H),IR, MS (ES) m/z (relative intensity): 355 (M⁺-p-TsOH, 100).

Anal. Calcd. for C₂₄H₃₂Cl₂N₄O₃S: C, 54.65; H, 6.11; N, 10.62.

Found: C, 56.95; H, 6.78; N, 9.02.

EXAMPLE 54-{[5-(2,2-Dimethyl-butylamino)-1,3-dimethyl-1H-pyrazol-4-ylamino]-methyl}-benzonitrileStep 1 N-(1,3-Dimethyl-1H-pyrazol-5-yl)-2,2-dimethyl-butyramide

The title compound was prepared according to the procedure of Example 1,Step 1 except that 2,2-dimethylbutyroyl chloride was used in place ofpivaloyl chloride. Brown oil, yield: 81%, ¹H NMR (300 MHz, CDCl₃): δ0.91(t, J=7.4 Hz, 3H), 1.25 (s, 6H), 1.63 (q, J=7.4 Hz, 2H), 2.20 (s, 3H),3.61 (s, 3H), 7.34 (brs, 1H), IR (KBr, cm⁻¹): 3293m, 2968s, 2938s,2879w, 1667s, 1565s, 1511-1447brs, 1381m, 1285w, 1161w, 774m., MS (ES)m/z (relative intensity): 210 (M⁺+H, 100).

Anal. Calcd. for C₁₁H₁₉N₃O: C, 63.13; H, 9.15; N, 20.08.

Found: C, 61.83; H, 9.15; N, 18.54.

Step 2 (2,2-Dimethyl-pentyl)-(2,5-dimethyl-2H-pyrazol-3-yl)-amine

The title compound was prepared according to the procedure of Example 1,Step 2. Yellow oil, yield: 91%, ¹H NMR (300 MHz, CDCl₃): δ0.89 (t, 3H),0.95 (s, 6H), 1.33 (q, 2H), 2.15 (s, 3H), 2.82 (d, 2H), 3.55 (s, 3H),δ5.25 (s, 1H).

Step 3(2,2-Dimethyl-butyl)-(2,5-dimethyl-4-nitroso-2H-pyrazol-3-yl)-amine

The title compound was prepared according to the procedure of Example 1,step 3. Purple solid, yield: 50%, mp: 45-50° C., ¹H NMR (300 MHz,CDCl₃): δ0.89 (t, 3H), 0.97 (s, 6H), 1.37 (q, 2H), 2.61 (s, 3H), 3.25(d, 2H), 3.76 (s, 3H), IR (KBr, cm⁻¹): 2963s, 2878m, 1632s, 1550s,1528w, 1477m, 1370m, 1356w, 1285w, 1228m, 1134m, 1080w, 967m, 655w, MS(ES) m/z (relative intensity): 225 (M+H^(+,) 100).

Anal. Calcd. for C₁₁H₂₀N₄O: C, 58.90; H, 8.99; N, 24.98.

Found: C, 58.14; H, 8.75; N, 25.56.

Step 4 N(3)-(2,2-Di methyl-pentyl)-2,5-dimethyl-2H-pyrazole-3,4-diamine

The title compound was prepared according to the procedure of Example 1,step 4. Yellow oil, yield: 82%, ¹H NMR (300 MHz, CDCl₃): δ0.89 (t, 3H),0.95 (s, 6H), 1.33 (q, 2H), 2.15 (s, 3H), 2.78 (s, 2H), 3.65 (s, 3H).

Step 54-{[5-(2,2-Dimethyl-butylamino)-1,3-dimethyl-1H-pyrazol-4-ylamino]-methyl}-benzonitrile

The title compound was prepared according to the procedure of Example 1,Step 5 except that 4-cyanobenzaldehyde was used in place of4-pyridinecarboxaldehyde andN(3)-(2,2-dimethyl-pentyl)-2,5-dimethyl-2H-pyrazole-3,4-diamine was usedin place ofN(3)-(2,2-dimethyl-propyl)-2,5-dimethyl-2H-pyrazole-3,4-diamine. Yellowoil, yield: 19%, ¹H NMR (300 MHz, CDCl₃): δ0.83 (t, 3H), 0.89 (s, 6H),1.28 (q, 2H), 2.10 (s, 3H), 2.61 (s, 2H), 3.59 (s, 3H), 4.04 (s, 2H),7.42 (d, 2H), 7.61 (d, 2H), IR (KBr, cm⁻¹): 3340m, 2961s, 2877m, 2226s,1588m, 1565m, 1537m, 1462m, 1378m, 1365m, 1296w, 821w, MS (ES) m/z(relative intensity): 326 (M+H⁺, 100).

Anal. Calcd. for C₁₉H₂₇N₅: C, 70.12; H, 8.36; N, 21.52.

Found: C, 68.87; H, 8.49; N, 20.92.

EXAMPLE 6N(4)-(2,4-Difluoro-benzyl)-N(3)-(2,2-dimethyl-propyl)-2,5-dimethyl-2H-pyrazole-3,4-diamine

The title compound was prepared according to the procedure of Example 1,Step 5 except that 2,4-difluorobenzaldehyde was used in place of4-pyridinecarboxaldehyde. Yellow gum, yield: 61%, ¹H NMR (300 MHz,CDCl₃): δ0.96 (s, 9H), 2.07 (s, 3H), 2.62 (s, 2H), 3.59 (s, 3H), 3.97(s, 2H), 6.77-6.86 (m, 2H), 7.13-7.24 (m, 1H), IR (KBr, cm⁻¹): 3300 m,2960s, 2870m, 1588m, 1531m, l500s, 1433m, 1230m, 1176m, 1125m, MS (ES)m/z (relative intensity): 323 (M+H⁺, +100).

Anal. Calcd. for C₁₇H₂₄F₂N₄: C, 63.33; H, 7.50; N, 17.38.

Found: C, 62.61; H, 7.59; N, 17.14.

EXAMPLE 7N(3)-(2,2-Dimethyl-propyl)-2,5-dimethyl-N(4)-pyridin-3-ylmethyl-2H-pyrazole-3,4-diamine

The title compound was prepared according to the procedure of Example 1,Step 5 except that 3-pyridinecarboxaldehyde was used in place of4-pyridinecarboxaldehyde. Yellow gum, yield: 39%, ¹H NMR (300 MHz,CDCl₃): δ0.94 (s, 9H), 2.12 (s, 3H), 2.58 (s, 2H), 3.59 (s, 3H), 4.00(s, 2H), 7.23(m, 1H), 7.60(m, 1H), 8.55(m, 2H), IR (KBr, cm¹): 3289m,3029w, 2953s, 2867m, 1589m, 1532w, 1478s, 1424m, 1394m, 1296m, 1138m,1079m, 714m, MS (ES) m/z (relative intensity): 288 (M+H⁺, 100).

Anal. Calcd. for C₁₆H₂₅N₅: C, 66.87; H, 8.77; N, 24.37.

Found: C, 65.20; H, 8.98; N, 23.69.

EXAMPLE 8N(3)-(2,2-Dimethyl-propyl)-2,5-dimethyl-N(4)-(2,4,6-trimethyl-benzyl)-2H-pyrazole-3,4-diamine

The title compound was prepared according to the procedure of Example 1,Step 5 except that 2,4,6-trimethylbenzaldehyde was used in place of4-pyridinecarboxaldehyde. Tan solid, yield: 47%, mp: 114-120° C., ¹H NMR(300 MHz, CDCl₃): δ0.91 (s, 9H), 2.19 (s, 3H), 2.25 (s, 3H), 2.32 (s,6H), 2.46 (s, 2H), 3.59 (s, 3H), 3.96 (s, 2H), 6.84(s, 2H), IR (KBr,cm⁻¹): 3322 m, 3283s, 2951s, 2922m, 2878m, 2823w, 1583m, 1476s, 1452m,1285s, 1196m, 851w, 757w, MS (ES) m/z (relative intensity): 329 (M+H⁺,100).

Anal. Calcd. for C₂₀H₃₂N₄: C, 73.13; H, 9.82; N, 17.06.

Found: C, 73.12; H, 9.97; N, 17.05.

EXAMPLE 9 N( 3)-(2,2-Dimethyl-butyl)-2,5-dimethyl-N(4)-pyridin-4-ylmethyl-2H-pyrazole-3,4-diamine

The title compound was prepared according to the procedure of Example 5,Step 5 except that 4-pyridinecarboxaldehyde was used in place of 4-cyanobenza ldehyde. Purple oil, yield: 49%, ¹H NMR (300 MHz, CDCl₃): δ0.83(t, 3H), 0.89 (s, 6H), 1.29 (q, 2H), 2.13 (s, 3H), 2.61 (s, 2H),2.81(br, 2H), 3.60 (s, 3H), 4.01 (s, 2H), 7.27 (d, 2H), 8.55(d, 2H), IR(KBr, cm⁻¹): 3296m, 2970s, 2877m, 1601s, 1462m, 1418m, 1378m, 1296m,1138w, 993w, 799w, 405w, MS (ES) m/z (relative intensity): 302 (M+H⁺,100).

Anal. for C₁₇H₂₇N₅: C, 67.74; H, 9.03; N, 23.23.

Found: C, 66.82; H, 9.05; N, 23.53.

EXAMPLE 10N(4)-Benzyl-N(3)-(2,2-dimethyl-butyl)-2,5-dimethyliNl-2H-pyrazole-3,4-diamine

The title compound was prepared according to the procedure of Example 5,Step 5 except that benzaldehyde was used in place of4icyanobenzaldehyde. Yellow oil, yield: 66%, ¹H NMR (300 MHz, CDCl₃):δ0.82 (t, 3H), 0.87 (s, 6H), 1.27 (q, 2H), 2.12 (s, 3H), 2.59 (s, 2H),2.61(br, 2H), 3.59 (s, 3H), 3.96 (s, 2H), 7.30 (m, 5H), IR (KBr, cm⁻¹):3297m, 3207w, 2970s, 2877m, 1587m, 1461s, 1377m, 1294m, 1136w, 1081w,746m, 699s, MS (ES) m/z (relative intensity): 301 (M+H⁺, 100).

Anal. Calcd. for C₁₈H₂₈N₄: C, 71.96; H, 9.39; N, 18.65.

Found: C, 71.02; H, 9.33; N, 17.96.

EXAMPLE 11N(3)-(2,2-Dimethyl-propyl)-2,5-dimethyl-N(4)-phenyl-2H-pyrazole-3,4-diamine

To 300 mg (2.55 mmol) ofN(3)-(2,2-dimethyl-propyl)-2,5-dimethyl-2H-pyrazole-3,4-diamine and 20mL toluene was added 155 mg (0.51 mmol) P(o-tolyl)₃, 343 mg (3.57 mmol)NaOt-Bu, 0.27 mL (400 mg, 2.55 mmol) of bromobenzene and 116 mg (0.128mmol) of Pd₂dba₃, and the resulting purple mixture was heated to 100° C.After 5 h, the black reaction mixture was filtered through Celite andthe filtrate was poured into 50 mL brine. This aqueous mixture waswashed with 3×50 mL EtOAc, and the combined organics were dried overMgSO₄, filtered and evaporated to a brown oil. Flash chromatography onsilica gel, eluting with CH₂Cl₂/EtOAc (20/1 to 8/1 to 4/1) gave 402 mg(1.48 mmol, a 58% yield) of the title compound as a light yellow gum. ¹HNMR (300 MHz, CDCl₃): δ0.88 (s, 9H), 2.02 (s, 3H), 2.78 (brs, 2H),2.90-3.12 (brs, 1H), 3.67 (s, 3H), 4.71 (brm, 1H), 6.55-6.60 (m, 2H),6.72 (t, J=6.4 Hz, 1H), 7.15 (t, J=7.3 Hz, 2H), IR (KBr, cm⁻¹): 3390m,3262w, 3174w, 3058w, 2955m, 1602s, 1544m, 1516m, 1497s, 1476m, 1394m,1316s, 991w, 749m, MS (ES) m/z (relative intensity): 273 (M⁺+H, 100).

Anal. Calcd. for C₁₆H₂₄N₄: C, 70.55; H, 8.88; N, 20.57.

Found: C, 70.00; H, 9.20; N, 19.31.

EXAMPLE 12N(4)-(4-Chloro-2-methyl-phenyl)-N(3)-(2,2-dimethyl-propyl)-2,5-dimethyl-2H-pyrazole-3,4-diamine

The title compound was prepared according to the procedure of Example 11except that bromobenzene was replaced with 2-chloro-5-bromotoluene.Orange gum, yield: 56%, ¹H NMR (300 MHz, CDCl₃): δ0.87 (s, 9H), 1.99 (s,3H), 2.77 (s, 2H), 3.02 (brs, 1H), 3.67 (s, 3H), 4.52 (s, 1H), 6.32 (d,J=8.4 Hz, 1H), 6.96 (dd, J=2.1, 8.4 Hz, 1H), 7.05 (d, J=2.2 Hz, 1H), IR(KBr, cm⁻¹): 3344w, 3282s, 2952s, 2868m, 1580m, 1503s, 1479s, 1460m,1432m, 1308s, 1137m, 814w, MS (ES) m/z (relative intensity): 321 (M+,100).

Anal. Calcd. for C₁₇H₂₅ClN₄: C, 63.64; H, 7.85; N, 17.46.

Found: C, 63.95; H, 7.81; N, 16.47.

EXAMPLE 134-[5-(2,2-Dimethyl-propylamino)-1,3-dimethyl-1H-pyrazol-4-ylamino]-benzonitrile

The title compound was prepared according to the procedure of Example 11except that bromobenzene was replaced with 4-cyanobenzaldehye.Light-yellow solid, Yield 54%, mp: 131-134, ¹H NMR (300 MHz, CDCl₃):δ0.87 (s, 9H), 2.01 (s, 3H), 2.79 (brs, 2H), 3.02 (brs, 1H), 3.66 (s,3H), 5.21 (s, 1H), 6.58 (d, J=8.7 Hz, 2H), 7.42 (d, J=8.7 Hz, 2H), IR(KBr, cm⁻¹): 3360w, 2961m, 2222m, 1609s, 1515m, 1327w, 1169w, 828w, MS(ES) m/z(relative intensity): 296 (M⁺−H, 50).

EXAMPLE 14N(4)-(4-Chloro-phenyl)-N(3)-(2,2-dimethyl-propyl)-2,5-dimethyl-2H-pyrazole-3,4-diamine

The title compound was prepared according to the procedure of Example 11except that bromobenzene was replaced with 4-bromochlorobenzene. Yellowgum, yield: 56%, ¹H NMR (300 MHz, CDCl₃): δ0.88 (s, 9H),1.80-2.15 (brs,1H), 2.00 (s, 3H), 2.78 (s, 2H), 3.65 (s, 3H), 4.72 (brs, 1H), 6.49 (d,J=8.8 Hz, 2H), 7.09 (d, J=8.8 Hz, 2H), IR (KBr, cm⁻¹): 3262m, 3087w,2955s, 2867m, 1597s, 1491brs, 1394m, 1365m, 1312s, 1253m, 1207w, 1089w,821m, MS (ES) m/z (relative intensity): 307 (M⁺+H, 100).

Pharmacology

The smooth muscle relaxing activity of the compounds of this inventionwas established in accordance with standard pharmaceutically acceptedtest procedures with representative compounds as follows:

Sprague-Dawley rats (150-200 g) are rendered unconscious by CO₂asphyxiation and then euthanized by cervical dislocation. The bladder isremoved into warm (37° C.) physiological salt solution (PSS) of thefollowing composition (mM): NaCl, 118.4; KCl, 4.7; CaCl₂, 2.5; MgSO₄,4.7; H₂O, 1.2; NaHCO₃, 24.9; KH₂PO₄, 1.2; glucose, 11.1; EDTA, 0.023;gassed with 95% O₂; 2/5% CO₂; pH 7.4. The bladder is opened and then cutinto strips 1-2 mm in width and 7-10 mm in length. The strips aresubsequently suspended in a 10 mL tissue bath under an initial restingtension of 1.5 g. The strips are held in place by two surgical clips oneof which is attached to a fixed hook while the other is attached to anisometric force transducer. The preparations, which usually exhibitsmall spontaneous contractions, are allowed to recover for a period of 1hour prior to a challenge with 0.1 μM carbachol. The carbachol is thenwashed out and the tissue allowed to relax to its resting level ofactivity. Following a further 30 min period of recovery an additional 15mM KCl are introduced into the tissue bath. This increase in KClconcentration results in a large increase in the amplitude ofspontaneous contractions (and initiation of contractions in previouslyquiescent strips) superimposed upon a small increase in basal tone.Following stabilization of this enhanced level of contractile activity,incremental increases in the concentration of test compound or vehicleare introduced into the tissue bath. Contractile activity is measuredfor each compound or vehicle concentration during the last minute of a30 minute challenge.

The isometric force developed by the bladder strips is measured using aconcentration required to elicit 50% inhibition of pre-drug contractileactivity (IC₅₀ concentration) and is calculated from thisconcentration-response curve. The maximum percentage inhibition ofcontractile activity evoked by a test compound is also recorded forconcentrations of test compound less than or equal to 30 μM.

The results of this study are shown in Table I.

TABLE I Inhibition of Contractions in Isolated Rat Bladder StripsCompound n IC₅₀ (μM) Example 1 2 4.9 Example 2 2 8.26 Example 3 2 11.45Example 4 2 11.8 Example 5 1 12.6 Example 6 2 13.5 Example 7 1 15.4Example 8 1 17.8 Example 9 2 19.2 Example 10 2 19.9 Example 11 4 4.3Example 12 2 12.5 Example 13 2 17.9 Example 14 1 22.9 Example 15 2 10.7

In addition, we tested the ability of compounds to inhibit thehyperactivity of hypertrophied bladder (detrusor) smooth muscle inconscious female rats with hypertrophied bladders and thereby alleviateurinary incontinence in rats according to the following protocoldescribed by Malmgren et al. (J. Urol. 1989, 142, 1134.):

Female Sprague-Dawley rats, ranging in weight from 190-210 g are used.Up to 25 animals are prepared each time. After development of bladderhypertrophy 4-8 animals are used per test.

Compounds are dissolved in PEG-200 and administered by gastric gavage orintravenously in a volume of 5 mL/kg. For primary screening all drugsare administered at the arbitrary dose of 10 mg/kg p.o. to groups of 4rats.

The animals are anesthetized with halothane. Through a midline incisionthe bladder and urethra are exposed and a ligature of 4-0 silk is tiedaround the proximal urethra in the presence of a stainless steel rod (1mm diameter) to produce a partial occlusion. The rod is then removed.The abdominal region is closed using surgical staples and each ratreceives 150,000 units of bicillin C-R. The animals are allowed sixweeks to develop sufficient bladder hypertrophy. After six weeks, theligature is removed under halothane anesthesia and a catheter (PE 60)with a cuff is placed in the dome of the bladder and secured with apurse string suture. The catheter is tunneled under the skin andexteriorized through an opening in the back of the neck. The abdominalincision is sutured and the free end of the catheter sealed. In order toprevent infections the rats receive an injection of bicillin C-R (150000units/rat). Two days later the animals are used in cystometricalevaluations, The animals are placed in the metabolic cages and thecatheter is attached (using a “T” connector) to a Statham pressuretransducer (Model P23Db) and to a Harvard infusion pump. A plasticbeaker attached to a force displacement transducer (Grass FTO3) isplaced under the rat's cage to collect and record urine volume. Animalsare allowed 15-30 min to rest before the saline infusion (20 mL/hr for20 minutes) is started for the first cystometry period. Two hours afterthe first cystometry period, the rats are dosed with the vehicle or thetest compound and one hour later a second cystometry is performed. Thefollowing urodynamic variables are recorded:

Basal bladder pressure=the lowest bladder pressure during cystometry

Threshold pressure=bladder pressure immediately prior to micturition

Micturition volume=volume expelled

Micturition pressure=peak pressure during voiding

Basal bladder pressure = the lowest bladder pressure during cystometryThreshold pressure = bladder pressure immediately prior to micturitionMicturition volume = volume expelled Micturition pressure = peakpressure during voiding Spontaneous activity = mean amplitude of bladderpressure fluctuations during filling

Presentation of Results

The mean value of each variable is calculated before and after compoundadministration. For each compound the changes in the variables measuredare compared to the values obtained before treatment and expressed aspercent inhibition. The data are also subjected to 2-way analysis ofvariance to determine significant (p<0.05) changes in the variablemeasured.

Criteria for Activity

The most characteristic finding in this rat model is spontaneous bladdercontractions which develop during filling. The compounds which inhibitspontaneous contractions by at least 50% at 10 mg/kg p.o. or i.v.(arbitrary chosen dose) are considered active. The results of this studyare shown in Table II.

TABLE II Inhibition of Spontaneous Contractions In Vivo Compound # ofanimals dose mg/kg (p.o.) % Red (F)^(c) Example 1 4 10 mg/kg −36 ± 7^(c)Percent reduction in the total number of spontaneous contractions inthe hypertrophied rat bladder model

Hence, the compounds of this invention have a pronounced effect onsmooth muscle contractility and are useful in the treatment of urinaryincontinence, irritable bladder and bowel disease, asthma, hypertension,stroke, and similar diseases as mentioned above, which are amenable totreatment with potassium channel activating compounds by administration,orally parenterally, or by aspiration to a patient in need thereof.

Pharmaceutical Composition

Compounds of this invention may be administered neat or with apharmaceutical carrier to a patient in need thereof. The presentinvention accordingly provides a pharmaceutical composition whichcomprises a compound of this invention in combination or associationwith a pharmaceutically acceptable carrier. In particular, the presentinvention provides a pharmaceutical composition which comprises aneffective amount of a compound of this invention and a pharmaceuticallyacceptable carrier. The pharmaceutical carrier may be solid or liquid.

Applicable solid carriers can include one or more substances which mayalso act as flavoring agents, lubricants, solubilizers, suspendingagents, fillers, glidants, compression aids, binders ortablet-disintegrating agents or an encapsulating material. In powders,the carrier is a finely divided solid which is in admixture with thefinely divided active ingredient. In tablets, the active ingredient ismixed with a carrier having the necessary compression properties nsuitable proportions and compacted in the shape and size desired. Thepowders and tablets preferably contain up to 99% of the activeingredient. Suitable solid carriers include, for example, calciumphosphate, magnesium stearate, talc, sugars, lactose, dextrin, starch,gelatin, cellulose, methyl cellulose, sodium carboxymethyl cellulose,polyvinylpyrrolidine, low melting waxes and ion exchange resins.

Liquid carriers may be used in preparing solutions, suspensions,emulsions, syrups and elixirs. The active ingredient of this inventioncan be dissolved or suspended in a pharmaceutically acceptable liquidcarrier such as water, an organic solvent, a mixture of both orpharmaceutically acceptable oils or fat. The liquid carrier can containother suitable pharmaceutical additives such a solubilizers,emulsifiers, buffers, preservatives, sweeteners, flavoring agents,suspending agents, thickening agents, colors, viscosity regulators,stabilizers or osmo-regulators. Suitable examples of liquid carriers fororal and parenteral administration include water (particularlycontaining additives as above, e.g., cellulose derivatives, preferablesodium carboxymethyl cellulose solution), alcohols (including monohydricalcohols and polyhydric alcohols, e.g., glycols) and their derivatives,and oils (e.g., fractionated coconut oil and arachis oil). Forparenteral administration the carrier can also be an oily ester such asethyl oleate and isopropyl myristate. Sterile liquid carriers are usedin sterile liquid form compositions for parenteral administration.

Liquid pharmaceutical compositions which are sterile solutions orsuspensions can be utilized by, for example, intramuscular,intraperitoneal or subcutaneous injection. Sterile solutions can also beadministered intravenously. For oral administration, either a liquid orsolid composition form may be used.

The compositions are preferably adapted for oral administration.However, they may be adapted for other modes of administration, forexample, parenteral administration for patient suffering from heartfailure.

In order to obtain consistency of administration, it is preferred that acomposition of the invention is in the form of a unit dose. Suitableunit dose forms include tablets, capsules and powders in sachets orvials. Such unit dose forms may contain from 0.1 to 100 mg of a compoundof the invention and preferably from 2 to 50 mg. Still further preferredunit dosage forms contain 5 to 25 mg of a compound of the presentinvention. The compounds of the present invention can be administeredorally at a dose range of about 0.01 to 100 mg/kg or preferably at adose range of 0.1 to 10 mg/kg. Such compositions may be administeredfrom 1 to 6 times a day, more usually from 1 to 4 times a day.

The present invention further provides a compound of the invention foruse as an active therapeutic substance. Compounds of formula (I) are ofparticular use in the induction of smooth muscle relaxation. The presentinvention further provides a method of treating smooth muscle disordersin mammals including man, which comprises administering to the afflictedmammal an effective amount of a compound or a pharmaceutical compositionof the invention.

We claim:
 1. A method of treating disorders associated with spastic orexcessive smooth muscle contractions of the urinary tract in a mammal inneed thereof which comprises administration to said mammal of atherapeutically effective amount of a compound according to the formula

wherein: R¹ and R² are independently straight chain alkyl of 1 to 6carbon atoms, branched alkyl of 3 to 6 carbons atoms, or cycloalkyl of 3to 6 carbons atoms where R¹ and R² may be optionally substituted by F,Cl, Br, I, OH, NH₂, cyano, C₁-C₆ alkoxy, C₁-C₆ alkylthio, COOH orCOOC₁-C₆ alkyl; R³ is heteroaryl, optionally substituted with 1 to 4groups selected independently from straight chain C₁-C₆ alkyl, branchedalkyl of 3 to 6 carbons, or a cycloalkyl of 3 to 10 carbons; C₁-C₆alkoxy, cyano, F, Cl, Br, C₁-C₆ alkylthio, CO₂R¹, CONH₂, OH, NH₂, andNO₂; wherein heteroaryl is quinolizine, quinoline, isoquinoline,cinnoline, naphthyridine, and pyridine; R⁴ is a straight chain alkylgroup of 1 to 10 carbons atoms, a branched alkyl of 3 to 10 carbons, acycloalkyl of 3 to 10 carbons, all of which may be optionallysubstituted by one or more F or Cl atoms; n is 0 or 1; all crystallineforms; an enantiomer or diastereomer, or a pharmaceutically acceptablesalt thereof.
 2. The method according to claim 1 wherein the disordertreated is urge urinary incontinence.
 3. A process for the preparationof a compound of Formula I which comprises reacting a compound offormula II

wherein: R¹ and R² are independently straight chain alkyl of 1 to 6carbon atoms, branched alkyl of 3 to 6 carbons atoms, or cycloalkyl of 3to 6 carbons atoms where R¹ and R² may be optionally substituted by F,Cl, Br, I, OH, NH₂, cyano, C₁-C₆ alkoxy, C₁-C₆alkylthio, COOH orCOOC₁-C₆ alkyl; and R⁴ is a straight chain alkyl group of 1 to 10carbons atoms, a branched alkyl of 3 to 10 carbons, a cycloalkyl of 3 to10 carbons, all of which may be optionally substituted by one or more For Cl atoms; with (a) a compound of formula III

 wherein: R³ is heteroaryl, optionally substituted with 1 to 4 groupsselected independently from straight chain C₁-C₆ alkyl, branched alkylof 3 to 6 carbons, or a cycloalkyl of 3 to 10 carbons; C₁-C₆ alkoxy,cyano, F, Cl, Br, C₁-C₆ alkylthio, CO₂R¹, CONH₂, OH, NH₂, and NO₂;wherein heteroaryl is quinolizine, quinoline, isoquinoline, cinnoline,naphthyridine, and pyridine, in benzene or toluene as a solvent in thepresence of molecular sieves at room temperature, followed by treatmentwith hydrogen under a pressure of 1 atmosphere in the presence ofPd/BaSO₄ at room temperature, in a polar solvent to obtain a formula (I)compound where n is 1,

and R¹, R², R³, and R⁴ are as defined above; or (b), a compound of theformula

wherein R³ is as defined above; in benzene or toluene as a solvent inthe presence of Pd₂dba₃, P(o-tolyl)₃, and NaOt-Bu at 100° C. to obtain aformula (1) compound according to the formula

where n is 0 and R¹ and R² are independently straight chain alkyl of 1to 6 carbon atoms, branched alkyl of 3 to 6 carbons atoms, or cycloalkylof 3 to 6 carbons atoms where R¹ and R² may be optionally substituted byF, Cl, Br, I, OH, NH₂, cyano, C₁-C₆ alkoxy, C₁-C₆ alkylthio, COOH orCOOC₁-C₆ alkyl; R³ is heteroaryl, optionally substituted with 1 to 4groups selected independently from straight chain C₁-C₆ alkyl, branchedalkyl of 3 to 6 carbons, or a cycloalkyl of 3 to 10 carbons; C₁-C₆alkoxy, cyano, F, Cl, Br, C₁-C₆ alkylthio, CO₂R¹, CONH₂, OH, NH₂, andNO₂; wherein heteroaryl is quinolizine, quinoline, isoquinoline,cinnoline, naphthyridine, and pyridine; R⁴ is a straight chain alkylgroup of 1 to 10 carbons atoms, a branched alkyl of 3 to 10 carbons, acycloalkyl of 3 to 10 carbons, all of which may be optionallysubstituted by one or more F or Cl atoms.
 4. The method of claim 1wherein the mammal is a human.